850639981 has 8 divisors (see below), whose sum is σ = 906511104. Its totient is φ = 796342800.

The previous prime is 850639943. The next prime is 850640053. The reversal of 850639981 is 189936058.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 850639981 - 2⁹ = 850639469 is a prime.

It is a super-2 number, since 2×850639981² = 1447176754551360722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (850639901) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 392370 + ... + 394531.

It is an arithmetic number, because the mean of its divisors is an integer number (113313888).

Almost surely, 2^850639981 is an apocalyptic number.

It is an amenable number.

850639981 is a deficient number, since it is larger than the sum of its proper divisors (55871123).

850639981 is a wasteful number, since it uses less digits than its factorization.

850639981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 786971.

The product of its (nonzero) digits is 466560, while the sum is 49.

The square root of 850639981 is about 29165.7329926748. The cubic root of 850639981 is about 947.5059162404.

The spelling of 850639981 in words is "eight hundred fifty million, six hundred thirty-nine thousand, nine hundred eighty-one".